1. Field of the Invention
The present invention relates to connectors and specifically to high speed, shielded connectors having one or more integrated PCB assemblies.
2. Brief Description of Prior Developments
Right angle connectors are now widely used and available in many different configurations. For right angle connector structures, the usual method of manufacture comprises stitching terminals into a suitable housing followed by row-by-row tail bending of the terminal tails. However, the method of bending the tails of each of the terminals is complex, especially since the bending is different for each row. The bending for each row must be done in such a way that each of the board contact terminals extends substantially the same distance from the connector body. Moreover, each of said board contact terminals, in the assembled state of the connector, must be precisely positioned in such a way that the pattern of board contact terminals corresponds closely to the pattern of holes in the PCB into which they will be inserted. An additional difficulty is related to the EMI shielding of the tails for high-frequency applications. In particular for the latter difficulty, a controlled-impedance tail section is preferred with additional ground shielding options. Towards this end, it is known to subdivide the manufacture of such a connector into one part for accommodating contact terminals for mating contact with the contact terminal of a mating connector and a separate for the tail end. Separate shielding casings, if required in a right angled configuration, may be provided around each of the terminals within the connector. Although connectors manufactured in this way operate satisfactorily the manufacturing costs are high.
U.S. Pat. No. 4,571,014 shows a different approach for the manufacturing of right angle connectors using one or more PCB assemblies. Each of the PCB assemblies comprises one insulated substrate, one spacer, and one cover plate, all of which are attached to one another. The insulating substrate is provided with a predetermined pattern of conducting tracks, while ground tracks are provided between the conducting tracks. The conducting tracks are connected at one end to a female contact terminal and at the other end to a male contact terminal. Each of the cover plates is a conductive shield member.
In the arrangement according to U.S. Pat. No. 4,571,014, the insulating substrates are rather thick to allow plated blind holes to be made for the construction of female-type contacts for mating contact with male-type pins of a mating connector or the like. The female contacts are connected to conducting tracks on the surface of the insulating substrate through a thin metal tail extending from the plated blind hole through the material of the insulating substrate to the corresponding track. However, in practice it is very difficult to produce such constructions with thin metal tails in a cost effective and reliable way. Moreover, it is practically very difficult to produce deep plated blind holes having a plating of a uniform thickness. Because of the application of plated blind holes within the insulating substrates each of the printed circuit boards has to have a predetermined thickness which reduces the possibilities of miniaturization.
Another disadvantage of the connector known from this U.S. Pat. No. 4,571,014 is that the shield members, the insulating substrates and the spacers have to be aligned with small holes and are fixed to one another by conducting rivets or pins through the aligned holes; the holes in the insulating substrates are plated through-holes, thus establishing an electrical contact between each of the ground tracks between the conducting tracks and the shield members in the assembled state. However, in practice this is not a very reliable way of assuring electrical contact between the shield members and the ground tracks on the insulating substrates.
The object of the present invention is to provide a connector which overcomes the disadvantages described above.
This object is obtained by the present invention by providing a connector in which terminals are secured onto the surface of a PCB carrying a conductive trace. The portion of the terminal extending above the surface of the PCB is accommodated by recesses formed in an associated cover or in a spacer. By the arrangement of such a first set of one or more first recesses and a second set of one or more second recesses respective first and second contact terminals, either male or female, can be easily connected to the respective conducting tracks. No complicated plated blind holes are necessary to make female-type contact terminals since the recesses in the cover or the spacer provide enough space for accommodating formed contact terminals, such as a male or female terminal blanked from sheet stock.
In order to provide shielding between adjacent conducting tracks on the PCB, ground tracks may be provided between the conducting tracks on a first surface and a ground layer may be provided on a second surface opposite the first surface.
The cover plates are made of insulating material and may be provided with cover plate conducting tracks and cover plate ground tracks in a predetermined pattern on a first cover plate surface facing the insulating substrate. The cover plate conducting tracks may have one end for connection to one first contact terminal and another end for connection to one second contact terminal. The cover plates may have the second cover plate surface opposite said first cover plate surface covered by a cover plate ground layer. Thus, each of the first contact terminals may be connected to one second contact terminal through one conducting track on the insulating substrate and through a conducting track on the cover plate. Thereby, the electrical resistance between a first contact terminal and a respective second contact terminal is reduced. The pattern of conducting tracks on the insulating substrate and the pattern of conducting tracks on the cover plate may be in mirror relation to each other.
The ground tracks on the insulating substrate and the cover plate ground tracks on the cover plate, respectively, can be connected to the ground layer on the second surface of the insulating substrate and to the cover plate ground layer, respectively, through plated through-holes. This can be easily achieved, by starting the production of a connector according to the invention with an insulating substrate having metal layers at both sides. One side of the substrate is, then, patterned to be provided with suitable conducting tracks and ground tracks in a predetermined pattern, in accordance with known PCB manufacturing techniques. The ground tracks may then be electrically connected to the metal layer at the opposite side by plated through-holes, which can be made by well known manufacturing techniques.
The recesses in the spacer or cover plate can be designed for entirely accommodating one first contact terminal in such a way that, in the assembled state, none of the first contact terminals extends outside the connector. Such a configuration, used in conjunction with a shielding ground layer, provides improved shielding as it is possible to enclose each of the contact terminals to a greater extent.
The second contact terminals may comprise press-fit pins, surface mount terminals and solder contact pins for connecting the connector to a printed circuit board or the like.
The connector may also comprise an insulating connector body accommodating each of said one or more integrated PCB assemblies and provided with a metallized shielding layer on its outer surface. Thereby, the electromagnetic interference caused by such a connector to the environment is further reduced. The connector body desirably includes structure for receiving and securing PCB modules in alignment.
A simplified configuration results when in the connector according to the invention each spacer and its adjacent cover plate are substituted by another cover plate, provided with suitable recesses for accommodating first contact terminals and/or second contact terminals.
According to another feature of the invention, the PCB modules include planar insulating substrates having conductive traces on which terminals are secured and insulating covers disposed over the terminal carrying side of the substrate, the covers having recesses for accommodating the terminals. The covers and associated recesses can comprise a means of applying a force to the contact terminals, such as an insertion force necessary to press fit the connector into a circuit board, in a manner that minimizes or eliminates the imposition of stresses on the connection of the terminals to the circuit traces. The terminals include structure, engaged by the cover, for imparting force to the terminals.
The connector may be provided with suitable filter elements by arranging at least one electrical component within the connector, for instance selected from the group of components comprising resistors, capacitors and inductors.
The present invention will be further illustrated with reference to some drawings which are meant for illustration purposes only and not intended to limit the scope of the present invention.
In the drawings: